Multi-fault diagnosis method for electromechanical composite transmission system based on improved sliding-mode observer

Abstract

The invention discloses an electromechanical composite transmission system multi-fault diagnosis method based on an improved sliding mode observer, which is used for performing fault diagnosis on a transmission system and comprises the following steps of: establishing a state-space equation according to a relationship between a rotating speed and a torque; determining system variables, and constructing a fault system model; establishing a transmission system sliding-mode observer in combination with a sliding-mode control theory; establishing a residual dynamic equation according to the rotating speeds obtained by the observer and the sensor; clutch fault isolation is achieved through a logic fault isolation strategy; obtaining a fault reconstruction signal by using an equivalent output error injection concept, and judging the position and the fault type of a fault clutch; and acquiring a transmission system constraint behavior when the clutch breaks down, and judging the fault degree by combining with the vehicle speed. Aiming at the problems that the electromechanical composite transmission system has the clutch fault coupling characteristic and the fault type is difficult to effectively judge, the improved sliding mode observer fault diagnosis method is provided, fault isolation and reconstruction are achieved, the fault position and type are determined in time, and the fault diagnosis precision is remarkably improved.

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